Table of Contents
What always occurs after a chemical reaction?
Due to the absorption of energy when chemical bonds are broken, and the release of energy when chemical bonds are formed, chemical reactions almost always involve a change in energy between products and reactants.
What must happen for a reaction to happen?
For a chemical reaction to happen: reactant particles must collide with each other. the particles must have enough energy for them to react.
What two things must happen for a chemical reaction to take place?
How do reactions occur?
- Molecules must collide.
- Molecules must collide with enough energy to begin to break the old bonds so new bonds can form. ( Remember activation energy)
- Molecules must collide with the correct orientation.
How does reaction occur?
Reactions occur when two or more molecules interact and the molecules change. Bonds between atoms are broken and created to form new molecules. That’s it.
How can we know whether a reaction has taken place or not?
Some signs of a chemical change are a change in color and the formation of bubbles. The five conditions of chemical change: color change, formation of a precipitate, formation of a gas, odor change, temperature change.
What must be done to be certain that a chemical change has taken place?
What are four observations that a reaction is taking place?
Four possible clues that a chemical reaction has taken place are a change of temperature, a change of color, an emission of gas, and the presence of an odor.
How can you tell if a chemical reaction has taken place?
This is NOT to be confused with physical changes during heating and cooling when a substance melts or solidifies for example. We can tell if a chemical reaction has taken place when one or more of the following things happen: There has been a colour change inside the reaction flask. A gas has formed.
What happens to atoms during a chemical reaction?
The important message of this chapter is that atoms are rearranged during a chemical reaction. The atoms do not change, but how they are arranged in relation to each other does change. That means that the molecules change, even though the number of each kind of atom present at the start of the reaction, stays the same throughout.
Which is the correct description of a chemical reaction?
The substance (or substances) initially involved in the chemical reaction are called reactants or reagents. Chemical reactions are usually characterized by a chemical change, and they yield one or more products, which usually have properties different from the reactants. Chemical reactions are represented by Chemical Equations.
How is the direction of a chemical reaction determined?
Indicates direction of reaction Remember that in a chemical reaction, matter is neither created nor destroyed and atoms cannot change their identity (e.g. a carbon atom can�t become an Iron atom); this means that you have to have the same number of each type of atom on each side of the chemical equation.